Evaluating the function of the heart is an important part of diagnosing and treating patients with heart disease, the leading cause of death and disability in the Western World. However, conventional means of assessing cardiac function have many limitations. Even invasive methods used for research purposes are limited to evaluation of only a limited portion of the heart wall; they also may themselves alter the motion of the portion of the heart being studied. The right ventricle (RV) is even more difficult to study than the left (LV). Magnetic resonance imaging (MRI), used with noninvasive tissue tagging with spatial modulation of magnetization (SPAMM), provides a new method of quantitatively studying the detailed motion patterns within the heart wall. In previous research, MRI methods have been developed for using SPAMM to study the heart, along with methods to analyze the resulting tagged images, which have been incorporated in an integrated program, SPAMMVU. This has made it possible to begin studying the effects of a number of heart diseases on cardiac function, in significantly more detail than was previously possible. However, more basic work needs to be done, both to more fully exploit the capabilities of SPAMM-tagged MRI to study the full 3-dimensional motion of the ventricles and to make these methods more practical for clinical application. In this application, it is specifically proposed: 1) to further develop the capabilities of SPAMM-tagged MRI and SPAMMVU to study the full 3D motion of both the LV and RV, 2) to make the use of these methods more clinically relevant, and 3) to use SPAMM to study a series of patients with RV disease, as a preliminary evaluation of the clinical capabilities of SPAMM methods. Accomplishment of these aims will provide a new tool for cardiac function evaluation.for both research and clinical applications, and should lead to both a better understanding of normal and abnormal heart function and a more sensitive and accurate means for guiding the clinical management of individual patients.